Cold and Snowy Conditions Dominate Delaware’s 2014-15 Winter Season

Winter Temperatures

Preliminary data indicates that Delaware’s winter (December, January and February) temperature was below the 1981-2010 normal for the second year in a row. The Statewide mean winter temperature of 33.1°F was 3.2°F below the 30-year normal of 36.3°F. The 2014-15 winter season was the 30th coolest since records began in 1895 (Figure 1).

Winter Precipitation

Cold temperatures were accompanied by above normal precipitation across the state during the winter season. The statewide mean precipitation of 11.05” was 1.29” above the 1981-2010 normal of 9.76”, and was the second winter in a row with above normal values, and the 34th wettest winter since records began in 1895 (Figure 2).

Statewide Spatial Averages

Mean winter temperatures across the state were cold throughout, with temperatures ranging from 2.5°F to as much as 6.5°F below the 30-year mean (Figure 3). Precipitation across the State was highest across Sussex County, with values of over 12 inches in several locations (Figure 4). Winter precipitation values were lower over New Castle County, DE and Chester County, PA, with values generally less than 10 inches.

The colder than normal temperatures, combined with ample precipitation resulted in snowfall totals that were generally above normal across most of the State. Fifteen snowfall events dropped measurable snow on the First State during the winter season. Snowfall during the months of November through March (Delaware’s typical snowfall season) was greater than 20 inches across most of northern New Castle County, DE and Chester County, PA (Figure 5). Snowfall across Kent and Sussex Counties generally ranged from 13 to nearly 20 inches.

Figure 3. Winter 2014-15 average temperature departures from the 1981-2010 mean based upon DEOS station data.

Figure 4. Winter 2014-15 total precipitation based upon DEOS station data.